diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -121,7 +121,7 @@ mysqlclient==2.1.1
 nbconvert==7.7.3
   beautifulsoup4==4.11.2
     soupsieve==2.4
-  bleach==6.0.0
+  bleach==6.1.0
     six==1.16.0
     webencodings==0.5.1
   defusedxml==0.7.1
diff --git a/rhodecode/lib/markup_renderer.py b/rhodecode/lib/markup_renderer.py
--- a/rhodecode/lib/markup_renderer.py
+++ b/rhodecode/lib/markup_renderer.py
@@ -424,11 +424,13 @@ class MarkupRenderer(object):
     @classmethod
     def jupyter(cls, source, safe=True):
         from rhodecode.lib import helpers
+        from .html_sanitizer_defs import markdown_attrs, all_tags, all_styles
 
         from traitlets import default, config
         import nbformat
         from nbconvert import HTMLExporter
         from nbconvert.preprocessors import Preprocessor
+        from nbconvert.preprocessors.sanitize import SanitizeHTML
 
         class CustomHTMLExporter(HTMLExporter):
 
@@ -439,24 +441,20 @@ class MarkupRenderer(object):
 
         class Sandbox(Preprocessor):
 
-            def preprocess(self, nb, resources):
+            def preprocess_cell(self, cell, resources, cell_index):
+                if not safe:
+                    return cell, resources
                 sandbox_text = 'SandBoxed(IPython.core.display.Javascript object)'
-                for cell in nb['cells']:
-                    if not safe:
-                        continue
+                if cell.cell_type == "markdown":
+                    cell.source = cls.sanitize_html(cell.source)
+                    return cell, resources
 
-                    if 'outputs' in cell:
-                        for cell_output in cell['outputs']:
-                            if 'data' in cell_output:
-                                if 'application/javascript' in cell_output['data']:
-                                    cell_output['data']['text/plain'] = sandbox_text
-                                    cell_output['data'].pop('application/javascript', None)
-
-                    if 'source' in cell and cell['cell_type'] == 'markdown':
-                        # sanitize similar like in markdown
-                        cell['source'] = cls.sanitize_html(cell['source'])
-
-                return nb, resources
+                for cell_output in cell.outputs:
+                    if 'data' in cell_output:
+                        if 'application/javascript' in cell_output['data']:
+                            cell_output['data']['text/plain'] = sandbox_text
+                            cell_output['data'].pop('application/javascript', None)
+                return cell, resources
 
         def _sanitize_resources(input_resources):
             """
@@ -475,8 +473,29 @@ class MarkupRenderer(object):
 
         def as_html(notebook):
             conf = config.Config()
-            conf.CustomHTMLExporter.default_preprocessors = [Sandbox]
+            # TODO: Keep an eye on the order of preprocessors
+            conf.CustomHTMLExporter.default_preprocessors = [Sandbox, SanitizeHTML]
             conf.Sandbox.enabled = True
+            conf.SanitizeHTML.enabled = True
+            conf.SanitizeHTML.attributes = markdown_attrs
+            conf.SanitizeHTML.tags = all_tags
+            conf.SanitizeHTML.styles = all_styles
+            conf.SanitizeHTML.sanitized_output_types = {
+                "text/html",
+                "text/markdown",
+            }
+            conf.SanitizeHTML.safe_output_keys = {
+                "metadata",
+                "text/plain",
+                "text/latex",
+                "application/json",
+                "image/png",
+                "image/jpg"
+                "image/jpeg",
+                "image/svg",
+                "image/svg+xml"
+            }
+
             html_exporter = CustomHTMLExporter(config=conf)
 
             (body, resources) = html_exporter.from_notebook_node(notebook)
diff --git a/rhodecode/tests/lib/test_markup_renderer.py b/rhodecode/tests/lib/test_markup_renderer.py
--- a/rhodecode/tests/lib/test_markup_renderer.py
+++ b/rhodecode/tests/lib/test_markup_renderer.py
@@ -17,6 +17,7 @@
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
+import mock
 import pytest
 
 from rhodecode.lib.markup_renderer import (
@@ -778,8 +779,119 @@ def test_relative_links(src_html, expect
     """, "Hello, World!")
 ])
 def test_jp_notebook_html_generation(notebook_source, expected_output):
-    import mock
     with mock.patch('rhodecode.lib.helpers.asset'):
         body = MarkupRenderer.jupyter(notebook_source)
         assert "<!-- ## IPYTHON NOTEBOOK RENDERING ## -->" in body
         assert expected_output in body
+
+
+@pytest.mark.parametrize("notebook_source, expected_output", [
+    ({"cells": [
+        {
+            "cell_type": "code",
+            "execution_count": 0,
+            "metadata": {},
+            "outputs": [
+                {
+                    "data": {
+                        "text/html": [
+                            "<select><iframe></select><img src=x: onerror=alert('xss')>\n"
+                        ],
+                        "text/plain": []
+                    },
+                    "metadata": {},
+                    "output_type": "display_data"
+                }
+            ],
+            "source": [
+                ""
+            ]
+        }
+    ],
+         "metadata": {
+             "kernelspec": {
+                 "display_name": "Python 3",
+                 "language": "python",
+                 "name": "python3"
+             },
+             "language_info": {
+                 "codemirror_mode": {
+                     "name": "ipython",
+                     "version": 3
+                 },
+                 "file_extension": ".py",
+                 "mimetype": "text/x-python",
+                 "name": "python",
+                 "nbconvert_exporter": "python",
+                 "pygments_lexer": "ipython3",
+                 "version": "3.9.6"
+             }
+         },
+         "nbformat": 4,
+         "nbformat_minor": 5
+     }, '<select></select><img alt="No description has been provided for this image"/>'),
+    ({
+         "cells": [
+             {
+                 "cell_type": "markdown",
+                 "metadata": {},
+                 "source": [
+                     "<label for=buttonid style=\"cursor: text\">not safe to click here</label>\n"
+                 ]
+             },
+             {
+                 "cell_type": "markdown",
+                 "metadata": {
+                     "highlighter": "codemirror"
+                 },
+                 "source": "<div class=\"jp-InputArea-editor\"><div class=\"CodeMirror cm-s-jupyter\"><div class=\"CodeMirror-scroll\"><div class=\"CodeMirror-sizer\"><div style=\"top:0px; position:relative\"><div class=\"CodeMirror-lines\"><div style=\"outline:none; position:relative\"><div class=\"CodeMirror-code\"><div style=\"position: relative\"><label for=buttonid style=\"cursor: text\"><pre class=\"CodeMirror-line\" style=\"background:transparent\"><span style=\"padding-right: 0.1px\"><span class=\"cm-builtin\">print</span>(<span class=\"cm-string\">&quot;Also not safe to click here&quot;</span>)</span></pre></label></div></div></div></div></div></div></div></div></div>"
+             },
+             {
+                 "cell_type": "code",
+                 "execution_count": 0,
+                 "metadata": {
+                     "xrender": True
+                 },
+                 "outputs": [
+                     {
+                         "data": {
+                             "text/html": [
+                                 "<form id=jp-mk-edit action='javascript:alert(1)' style='display:none'><button type=submit id=buttonid></form>\n"
+                             ],
+                             "text/plain": []
+                         },
+                         "metadata": {},
+                         "output_type": "display_data"
+                     }
+                 ],
+                 "source": ""
+             }
+         ],
+         "metadata": {
+             "kernelspec": {
+                 "display_name": "Python 3",
+                 "language": "python",
+                 "name": "python3"
+             },
+             "language_info": {
+                 "codemirror_mode": {
+                     "name": "ipython",
+                     "version": 3
+                 },
+                 "file_extension": ".py",
+                 "mimetype": "text/x-python",
+                 "name": "python",
+                 "nbconvert_exporter": "python",
+                 "pygments_lexer": "ipython3",
+                 "version": "3.9.6"
+             }
+         },
+         "nbformat": 4,
+         "nbformat_minor": 5
+     }, '<form style="display:none;">')
+])
+def test_jp_notebook_against_xss(notebook_source, expected_output):
+    import json
+    with mock.patch('rhodecode.lib.helpers.asset'):
+        body = MarkupRenderer.jupyter(json.dumps(notebook_source))
+        assert expected_output in body